Outer space is defined as the vacuum beyond the Earth's atmosphere, representing an environment characterized by near-perfect vacuum conditions and extreme temperature differentials. The physics of this domain are governed by gravity and orbital mechanics, dictating the movement of celestial bodies such as stars, planets, and galaxies. Because it lacks a substantial atmosphere or medium, the space environment exposes objects and systems to intense cosmic and solar radiation. Scientific study of this region focuses on fundamental physical processes, including stellar nucleosynthesis, the structure of galactic clusters, and the principles of propulsion necessary for interstellar travel.